Ok, I got upset at the keyboard and accidently answered my own earlier post. it might help other MAC users. If Shift-click is not working, nor any of the other suggestions helping, hold down the Apple key or Option key and then type N on the keyboard. It worked fine. Might another keyboard stroke that works on your keyboard, but give it a try. For the record, I use a Logitech optical mouse with left and right clicks as well as the scroll wheel. Nothing helped until I found the N factor.